However I do not know where to go from here, I can not seem to manipulate the and relate it with with any inequalities.

Thank you all!

Aug 15th 2010, 03:03 PM

Vlasev

I think you should use start with the fact that [LaTeX ERROR:
Compile failed]
.

Aug 16th 2010, 03:15 AM

usagi_killer

Thanks for that, I've played around with that however I still can not seem to get it :(

Aug 16th 2010, 04:10 AM

HallsofIvy

Try going to polar coordinates. With and , so that , . Now, just take some upper bound on (it certainly can't be larger than 2) and you have reduced to a one-variable, r, problem.

Aug 16th 2010, 04:16 AM

thorin

Hi,

So

now, we can use the fact that x.ln(x) has 0 for limit in 0 : with

Aug 16th 2010, 04:49 AM

Vlasev

HallsOfIvy, please refer to my post in http://www.mathhelpforum.com/math-he...es-153726.html to see an example where your method fails. It fails because there are other ways to approach the limit point, not just straight lines. There is no way to reduce the 2 dimensional problem to a 1 dimensional problem unless it has circular symmetry around the point.

Aug 16th 2010, 06:11 AM

usagi_killer

Quote:

Originally Posted by thorin

Hi,

So

now, we can use the fact that x.ln(x) has 0 for limit in 0 : with

Hi thanks for the help, however I am unclear how you got the first line of your working.

Thanks!

Aug 16th 2010, 06:20 AM

Vlasev

Quote:

Originally Posted by usagi_killer

Hi thanks for the help, however I am unclear how you got the first line of your working.